When Toby Jones first saw the BBC miniseries “Tinker Tailor Soldier Spy,” based on John le Carré’s classic 1974 espionage novel, he likened the experience to “being introduced to Shakespeare.” Even though he was too young to comprehend everything—the seven-part series aired when he was 12—“you could tell something important was going on,” says Mr. Jones, who co-stars in a new film based on the book.

Replicating the success of the book and the miniseries in a two hour film is a tall order: Mr. le Carré’s novels require intense concentration, and are known for their convoluted plots [For more, go to "The Perplexing Case of the Cerebral Thriller."] But the film, by Swedish director Tomas Alfredson (“Let the Right One In”) was a runaway hit in the U.K., where it spent three weeks at the top of the box office charts. It is also generating best actor buzz for Gary Oldman, who plays protagonist George Smiley. The film, which is being distributed in the U.S. by Focus Features, opens on Dec. 9.

Mr. Jones’s Hollywood career began to take off in 2006, when he starred in “Infamous” as Truman Capote. The film got good reviews but was a box office flop—it opened a year after Philip Seymour Hoffman’s Oscar winning star turn in “Capote”—generating a paltry $2.6 million globally. Since then, Mr. Jones has been cast in several Hollywood productions, including “Frost/Nixon,” “W.,” “Harry Potter and the Deathly Hallows: Part 1,” “My Week with Marilyn,” and the much anticipated “Hunger Games,” which comes out in March.

Speakeasy caught up with Mr. Jones while he was shooting “Snow White and the Huntsman” to talk about his latest role, as the politically connected but untalented spy Percy Alleline, in “Tinker Tailor,” and his career. Excerpts:

It’s interesting that you were in “Infamous,” which had a double and now you’re doing “Snow White and the Huntsman,” which also has a competing production “Mirror, Mirror” starring Julia Roberts as the Evil Queen.

Oh please, don’t even go there. I am doing this TV thing—this ITV/ABC version of Titanic. It’s a four part series. I was at the premiere of “My Week with Marilyn” last night and [actor] Derek Jacobi was there and he said “I’ve just been shooting this Titanic thing for TV” and it’s a totally different one. So if you ever want to make just one movie, don’t hire me, because there will always be some other movie being made. Oh my lord.

There’s a lot of subtlety in this film because all these guys are spies, and are suspicious of each other. Could you talk about what it was like to shoot these very quiet scenes with strong emotional undertones?

There are several highly charged scenes, five or six, around a table that are interesting for actors because the actor is a storyteller sustaining a story which is about withholding identity rather than declaring identity…it’s fascinating as an acting exercise to keep yourself a possible suspect so you are very hyper-aware of every minute gesture you do. If you are around a table, the fear you are doing too much, scratching your hand or involuntarily picking up a pen— you are giving away whether you are or aren’t a suspect. It’s a neurotic context to act in.

What would [director] Tomas Alfredson tell you to do, or not to do?

He’s very good at telling you what he’s seeing. It sounds like such a simple thing to do. He would say things like “I noticed when you entered the room you put your hand in the pocket. From that I took this meaning. Let’s try it without you putting your hand in your pocket.”

Percy Allilene is this subtly ambitious character – he’s also a Scotsman. Tomas Alfredson was telling me that there was some kind of indignity for an Englishman to have to report to a Scotsman…could you talk about that?

I think there is…what the British would call a very “clubby” atmosphere of secret codes and coded behavior and assumptions about class and if you add nationality into that you feel like a foreigner. British culture is very stratified in that way. There are these minute codes of behavior and dress. They mean many things that are there to exclude and I think that Alleline has a certain aggression that may well be to do with an inferiority complex…because I am slightly shorter than the other actors, slightly flashier dressed. All these things signal an assertion of a new regime that he wants to impose.

Do you think this film will be as popular in America as it is in the U.K.?

I think that the way it’s been directed, I’d be amazed if it was a box office smash hit. I don’t think it’s that kind of film. I think it has been directed in a way to appeal to an old genre—the spy genre—and a new reexamination of that genre. Speaking personally, it’s also fascinating view of England at a very specific time period. Most films of the 70s are a kitsch fest. Actually you sense a lot of the post-war hangover of Britain in this film. Not just the Cold War, but the Second World War hangover, the feeling that things are still quite damp and cold and painted over and not yet modern.

It’s such a hard book to translate into a movie – the characters are so in their heads and say so little.

What is miraculous in the film is the adaptation. When BBC did it—they had several hours. Here, in less than two and a half hours you feel like you’ve been steeped into that world. The plot itself requires a lot of concentration, nonetheless you feel like there’s a full dose of that world, and that atmosphere. The thing I really liked about the structure is that you’re introduced to a character and then you disappear down an alley with a character. The film explores all these corners of plots…traveling backwards and why a character did something, where a relationship was rooted.

Most espionage thrillers would be much more obvious, and require less concentration.

I think one of the pleasures of le Carré’s spy books is the feeling that you’re being treated as a clever person, not an idiot. And I think the film has something like that, as a member of the audience even if you don’t understand everything right the moment it happens you’re being treated as clever enough that you will eventually pick it up.